1. Database overview
Starting today, we will begin to learn the basics of the database
(1) Let's first understand briefly what the database does?
The database is used to store data, and the software we usually use will process a large amount of data. Some of the data processed by the software needs to be stored permanently, so it is definitely not possible for us to store the data in the memory. Because the data in the memory cannot be saved permanently, we need to save the data in the hard disk at this time. The data in the hard disk is saved in the file, but the data in the file will be very inconvenient to check. Therefore, we have introduced the concept of a database, a database management system can help us query and manage data well
(2) What is a database?
The database (DataBase) is a warehouse that organizes, stores and manages data according to the data structure. That is, it is usually a file or a group of files, which saves some data that meets specific specifications. The English word corresponding to the database is Database, abbreviated as: DB
Database software is called database management system (DBMS), full name: Database Management System
2. Data saving comparison
Data is saved in memory
Advantages: fast access speed
Disadvantages: data cannot be stored permanently
The data is saved in a file
Advantages: data is stored permanently
Disadvantages:
(1) The speed is slower than the memory operation, and there are frequent IO operations
(2) Inconvenient data query
Data is saved in the database
Features:
(1) Permanent storage of data
(2) The use of SQL statements makes querying convenient and efficient
(3) Convenient data management